This invention relates to an image recording apparatus which directly regulates and modulates a flow of toner particles for recording images.
Currently, an image recording apparatus which records images by jetting toner particles has been proposed, for example, in U.S. Pat. No. 3,689,935. According to the disclosure of this patent, the image recording apparatus comprises a toner supply, an aperture electrode having a plurality of apertures, and a back electrode. The toner supply provides charged toner particles, and projects the toner particles toward the aperture electrode. The aperture electrode, which regulates and modulates the flow of the toner particles, comprises an insulative layer provided with multiple apertures or holes, a first electrode layer coated on one side of the insulative layer, and a second insulative layer coated on the side of the insulative layer opposite to the first electrode layer. The second electrode layer includes multiple isolated segments which respectively surround each of the apertures. The back electrode facing the aperture electrode attracts and supports a support medium such as paper. The apparatus for recording images thus constructed controls the flow of the toner particles by applying electric signals individually to the aperture electrode and the back electrode, thereby recording images on the support medium.
However, upon recording images with the above-mentioned apparatus, the toner particles adhere to and block the apertures of the aperture electrode. More particularly, the inner diameter of the apertures must be approximately 50 .mu.m or less in order to obtain an image density of 240 DPI (dot per inch), since the maximum dot diameter is 100 .mu.m. As a result of residual charge from image signals and the like, the toner particles adhere to the aperture electrode due to the image force and the like. The toner particles thus block the small apertures, making the output images irregular.